title: Expression and secretion of the novel adipokine tartrate-resistant acid phosphatase from adipose tissues of obese and lean women.
abstract: OBJECTIVE
  Tartrate-resistant acid phosphatase (TRAP) expressed by adipose tissue macrophages (ATMs) induces mice obesity and human adipocyte differentiation in vitro. This study aimed to investigate whether TRAP was secreted differently from human obese versus lean adipose tissues and to identify the cellular source of adipose tissue TRAP.
  
  
  METHODS
  Subcutaneous adipose tissues obtained from healthy subjects. Enzyme-linked immunosorbent assays (ELISAs) for total (5a+5b) and cleaved TRAP (5b) were used. TRAP secretion was determined in adipose tissue biopsies, and mRNA expression was studied in cell types isolated from the same.
  
  
  METHODS
  Results of 24 lean and 24 obese women (in vitro) and 8 subjects (in vivo) were compared. The main outcome measurements were TRAP expression and secretion in vitro and in vivo.
  
  
  RESULTS
  In-house total TRAP ELISA showed high sensitivity and a coefficient of variance of 11%. Adipose secretion of total TRAP was linear in vitro with time and was evident in vivo. Total TRAP secretion in vitro was similar in lean and obese women expressed per unit weight of the adipose tissue but correlated positively with the number/size of adipocytes (P ≤ 0.01) and with adipose secretion of tumor necrosis factor-α and interleukin-6 (P<0.01). TRAP 5b was not secreted from the adipose tissue. ATMs displayed highest cellular expression of TRAP mRNA in adipose tissue cells derived from lean or obese women.
  
  
  CONCLUSIONS
  TRAP is a novel human adipokine produced by macrophages and secreted from the subcutaneous adipose tissue in vivo and in vitro. Secretion is linked to the size and number of adipocytes, as well as to concomitant secretion of inflammatory mediators, suggesting that TRAP is involved in fat accumulation and adipose inflammation.
authors.affiliation: Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Lång
authors.forename: A
authors.initials: A
authors.lastname: Zakaroff-Girard
authors.forename: K
authors.initials: K
authors.lastname: Wåhlén
authors.forename: J
authors.initials: J
authors.lastname: Andersson
authors.forename: T
authors.initials: T
authors.lastname: Olsson
authors.forename: C
authors.initials: C
authors.lastname: Bambace
authors.forename: J
authors.initials: J
authors.lastname: Jocken
authors.forename: A
authors.initials: A
authors.lastname: Bouloumié
authors.forename: G
authors.initials: G
authors.lastname: Andersson
authors.forename: P
authors.initials: P
authors.lastname: Arner
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D054392:Adipokines / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001835:Body Weight; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007333:Insulin Resistance; D015850:Interleukin-6 / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008820:Mice, Obese; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D012333:RNA, Messenger; D050151:Subcutaneous Fat / Q000378:metabolism*; D000071681:Tartrate-Resistant Acid Phosphatase; D013851:Thinness / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D054392:Adipokines; D015415:Biomarkers; D015850:Interleukin-6; D007527:Isoenzymes; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase